Influence of Air Temperature on Physical Characteristics and Bioactive Compounds in Vacuum Drying of Arthrospira Spirulina A.P.Q. Larrosa, A.A. Comitre, L.B. Vaz, L.A.A. Pinto Journal of Food Process Engineering, 2017 The aim of this study was to evaluate the effects of different temperatures in vacuum drying of Arthrospira Spirulina sp. on the physical properties and on the bioactive compounds, and to compare with the traditional oven dryer. The samples were evaluated according to phycocyanin content, phenolic compounds, lipid oxidation, color parameters and rehydration. The phenolic methanol extracts were analyzed by FTIR, and thermal analysis (DSC), scanning electronic microscopy and X‐ray diffraction of the samples were also performed. The results showed that the characteristics of the dried products were influenced by the different temperatures of the drying methods. Vacuum drying at 40C was the more suitable to dry Arthrospira Spirulina sp. in relation to the characteristics products due to the minor losses of phycocyanin content, the great source of phenolic compounds, the minor lipid oxidation, the good rehydration capacity and the highest thermal stability.Pratical ApplicationsArthrospira Spirulina sp. is a microalgae which is a promising source of compounds with biological activity that could be used as functional ingredients, due to presence of pigments, phenolic compounds and fatty acids. However, this algae is very perishable and it should be dried after cultivation in order to prevent fungal deterioration. Phycocyanin content, phenolic compounds and lipid oxidation of the Arthrospira Spirulina sp. are affected by temperature and time drying processing. Thus, the vacuum drying process is a technique which leads to a product with best quality due to the low air temperatures and less oxygen content present in environment of dryer under subatmospheric pressure. Therefore, selection of the most appropriate technique and the drying conditions are very important to avoid major losses of bioactive compounds during the drying process of Arthrospira Spirulina sp.
Physicochemical characteristics of the Spirulina sp. dried in heat pump and conventional tray dryers Bruna R. Costa, Silva F. Rocha, Marla C. K. Rodrigues, Ricardo S. Pohndorf, Ana P. Q. Larrosa, et al. International Journal of Food Science and Technology, 2015 SummaryA comparative study of Spirulina drying in heat pump dryer (HPD) and in conventional tray dryer (CTD) was performed. The effects of the methods used for the sample were evaluated in relation to the operation kinetics and the characteristics of the dehydrated microalgae. The air temperatures were 50 and 60 °C, and the absolute humidity of HPD was ten times smaller than in CTD. The values of the total drying time of HPD were 40% inferior to the found in CTD, for both air temperatures. The highest preservation of the Spirulina characteristics was found in HPD and air temperature of 50 °C, and in this condition, the values of phycocyanin, total phenolic compounds and total antioxidant activity were 14%, 60% and 10% higher than the values to the found in the same condition for CTD, respectively. These results are showing that the drying method is decisive in the product quality dehydrated.
